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mixer linearity (Read 2646 times)
sivacha
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mixer linearity
Oct 20th, 2006, 9:48pm
 
can u suggest the best way to improve the linearity of a folded mixer??

by doing source degeneration the noise figure is increasing.
i have very tight constraints on noise figure and linearity.

are these inter-related??

thank you.......
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aaron_do
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Re: mixer linearity
Reply #1 - Oct 20th, 2006, 11:50pm
 
A folded mixer is just an amplifier plus a switching stage. Source degeneration will improve the amplifier linearity at the cost of noise figure and gain. You should be able to use any of the typical methods to improve your amplifier's linearity such as multiple gated transistors. Or you could use a low noise amplifier...

Another method i've seen is to use a current mode mixer followed by an IF transimpedance amplifier.

hope that helps

Aaron
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ACWWong
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Re: mixer linearity
Reply #2 - Oct 21st, 2006, 1:57pm
 
sivacha wrote on Oct 20th, 2006, 9:48pm:
are these inter-related??


generally yes, more linear means less gain & more noise... as Aaron suggested you can try different toplogies/circuit system lineup, but the usual method to break this catch22 is to increase power ...
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